All comes down to usage. If for self defense, reliability is #1 since distance will be less than 20 yards, accuracy really isn't an issue.
That being said, I've taken skill builders that go up to 40 yards and seen guys with very expensive rifles have terrible grouping and even miss the 12 inch circle target. And same guys missed the index card at 10 yards. Indian not the arrow.
Both cheap and expensive AR's functioned fine. The only jams I have seen was cause a guy likes to tinker with his rifles all the time. Even AK jams due to tinkering too much. Set it and forget it. Gas set wrong, trigger fell out (roll in came loose), optic loose, etc...
Now the above is for your recreational shooters (shoots 1-4x a month). IDK how reliability would work with an AR that was used 3-4x a week for months/years.
Personally, I have a $500 S&W M&P Sport II and she runs fine. I replaced the S&W buffer spring because Geissele had a sale, not because it was having issues. But the compression difference was pretty big. I did put in aftermarket trigger and hand guard shortly after buying it, so unknown how the factor parts would have held up after 4 years.
Unlike Mrs. CMO's bolt (cracked), mine works fine so far and her bolt that had a crack in it was like 2 years newer than mine.
I would say if your an instructor, then you need a more expensive name brand AR. Mainly for street credit of course. I mean you don't see John Lovell (Warrior Poet) with an Anderson AR build. He prob could run it like a champ though (Indian).
IDK much about AR's and distance shooting, but I would assume a DD is more accurate than a M&P past 300 yards. Same Indian and same type of optic. Correct if wrong. If it isn't more accurate, then name brand and flexing would be the only reason to get 1. That being said, I dont' see myself buying a DD or Noveske. I would not want to put her in the dirt if I did get 1 of these expensive AR's. Same reason why I don't buy expensive pistols like a NightHawk or Wilson 1911.